1. Field of the Invention
The present invention concerns an image-forming device such as an electrophotographic apparatus, etc.
2. Discussion of the Background
Image-forming device having a mechanism which varies the magnification ratio by moving mirrors and lenses is generally known. In such an image-forming device, the optical system comprises four mirrors including first through fourth mirrors which are arranged from the side of an original to the side of photosensitive material, for example, in the order of a first mirror, second mirror, third mirror, through lens, fourth mirror, or in the order of the first mirror, second mirror, through lens, third mirror and fourth mirror.
Upon varying the magnification ratio, the optical distance between the original and the through lens and the optical distance between the through lens and the photosensitive material are changed by moving the through lens. Since the optical distance between the original and a drum has to be increased upon varying the magnification ratio, it has been adapted to move the second and the third mirrors in a device where these second and third mirrors are arranged ahead of the through lens, or to move the third and fourth mirrors interlocking with the movement of the through lens in a device where these third and fourth mirrors are arranged behind the through lens.
However, the mechanism is complicated in the system which moves the second and the third mirrors, particularly, when a both sides driving system is employed. Further, the interlocking moving mechanism is also complicated in the system which interlocks the third and the fourth mirrors with the movement of the through lens.
Further, an image-forming device such as an electrophotographic copying apparatus or laser printer, has a developing device adapted to deposit toners onto electrostatic latent images formed on a photosensitive material for visualizing them. In such a device, a toner hopper is disposed in an upper portion and toners are successively supplied from the toner hopper.
In a conventional image-forming device, which conducts two color reproduction, for example black and red, quite identical developing devices have been used for developing black color and developing red color except for merely changing the color of the toners contained in the toner hopper.
However, since quite identical devices have been used for the black color developing device and the red color developing device and their toner hoppers are disposed above the image-forming device, the space occupied by the developing section in the direction of the height is particularly increased to thereby enlarge the size of the image-forming device.